1. Field of the Invention
The present invention relates to closure alarm switches and more particularly, but not by way of limitation, to an alarm sensor mechanism to ensure alignment of magnetic sensor elements in a closure application.
2. History of the Prior Art
Door alarm mechanisms using magnetic sensor switching such as reed switches are well known as evidenced by the U.S. Pat. No. 3,771,153, issued Nov. 6, 1973 to Byrne. Such devices to be efficient and effective require that the two sensor elements be in rather accurate alignment when the door is in a closed position. When such devices are installed on close fitting windows, pivoting doors and the like, such alignment is normally obtainable.
However, alignment problems invariably occur when an attempt is made to utilize such devices on loosely fitting garage doors, overhead warehouse doors and the like. Simply attaching one sensor element to the door frame and the other to the door usually results in significant misalignment, giving rise to false alarms and/or incorrect status indications. Further, such misalignments can occur in all three mutually perpendicular planes.
Another problem associated with the installation of such sensors mechanisms on garage doors and overhead warehouse doors is that of inadvertently damaging the sensor mechanisms. Still another problem with the installation of such sensors is the ease in which the alarm system can be tampered with when the door mechanism is closed.